And while the actual cause of death is still unknown, the results are driving a wedge between the ASPCA — the organization that enforces the city’s laws against animal cruelty — and Mayor Michael Bloomberg, a longtime proponent of the horse and carriage trade.

“This is a horse that went to work at age 15. Without that, unfortunately, the horse probably would have been put down, and so at least it had a good life,” Bloomberg said Tuesday.

The ASPCA had an entirely different take.

“We — with all due respect to the mayor — don’t believe the choice is dying a bad death somewhere else, and perhaps suffering and dying on the city street working,” said Stacy Wolf, VP of the ASPCA’s Humane Law Enforcement division.

Wolf told 1010 WINS that the horse’s death brings to light the need to adjust the laws governing carriage horses.

“Certainly this issue and I think Charlie’s situation — the tragic situation — does I think highlight the fact that we need to take a hard look at making the law more protective when it comes to more thorough veterinary exams,” she said.

“This case just points out the treacherous life of a horse, whose job it is to drag around thousands of pounds of carriage and people,” said State Assemblywoman Linda Rosenthal.

Rosenthal said she’s gotten more than 5,000 letters and e-mails in the last few months supporting her state bill to ban horse-drawn carriages.

Supporters of the industry point to tougher laws enacted last year, including one that states the horses must be examined by a veterinarian twice each year.

But the ASPCA said a cursory exam wouldn’t have necessarily shown Charlie was in any pain, while a post-mortem examination showed he clearly was.

“Our excellent veterinarian does believe that in all likelihood, he certainly could have suffered discomfort or pain from those conditions,” Wolf said.

The ASPCA said Charlie had only been working as a carriage horse for a few weeks before he died and said in a statement on its website that “Charlie was not healthy for a career in an urban carriage horse business.”

“We are very concerned that Charlie was forced to work in spite of painful maladies, and these particular health issues can be difficult to diagnose because draft horses are by nature a stoic breed, not displaying signs of pain until they are very severe,” DVM Pamela Corey with the ASPCA said in the statement.

Last week, Mayor Michael Bloomberg said carriage horses in the city are fortunate to be working.

“Most of them probably wouldn’t be alive if they didn’t have a job,” Bloomberg said.